Method and system of ultrahigh resolution phase difference measurement

Abstract

The invention discloses a method and a system of ultrahigh resolution phase difference measurement with phase difference correction function and based on double-coincidence detection. The method includes the steps that: a. a measurement gate is formed by means of double phase coincidence detection between two pilot frequency signals, a first phase coincidence detection and coincidence pulse generating circuit conducts phase coincidence detection to a detected frequency signal and a public frequency signal and generates coincidence pulse; b. a second phase coincidence detection and coincidence pulse generating circuit conducts phase coincidence detection to a reference frequency signal and the public frequency signal and generates coincidence pulse; c. a gate-time generating circuit generates a gate-time signal according to a received enabling signal and a received closing signal, and a single chip computer obtains phase difference of the detected frequency signal and the reference frequency signal according to count data; and d. the coincidence pulse is counted within the time range near the enabling time and closing time of the measurement gate and a corrected value of the phase difference is obtained. Lastly, the ultrahigh resolution phase difference measurement is accomplished. By means of the method and the system of ultrahigh resolution phase difference measurement, counting error is eliminated, measuring resolution ration is high, and long time drift distance is small.

Description

technical field [0001] The invention belongs to the technical field of time-frequency signal processing, and in particular relates to a method and system for ultra-high resolution phase difference measurement based on dual composite detection with phase difference correction. Background technique [0002] High-resolution phase difference measurement technology is widely used in scientific research and engineering practice, and plays an important role in the field of time-frequency measurement and control. In electronic measurement, high-resolution phase difference measurement modules are included in high-precision test instruments such as oscilloscopes, logic analyzers, and signal generators. Satellite-ground time synchronization, navigation and positioning, laser ranging, communication technology and other fields in engineering applications also require high-resolution phase difference measurement technology. High-resolution phase difference measurement technology is the c...

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Problems solved by technology

The analog interpolation method uses the capacitance charging and discharging method to improve the measurement resolution, but the measurement resolution is limited by the filling clock frequency, and at the same time, it is susceptible to noise interference when the measured signal frequency is high

The time-to-digital conversion method and the vernier method use the delay line method to improve the measurement resolution, but the measurement resolution is limited by the resolution of the delay line, generally on the order of hundreds of picoseconds

The double-mixing time-of-flight method uses an intermediate crystal oscillator to measure the phase difference, and the resolution can reach the level of picoseconds. However, due to the influence of the intermediate crystal oscillator, this method has a large long-term measurement drift and is not suitable for long-term continuous measurement.

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